class Phone:
    __is_5g_enable=False

    def __check_5g(self):
        if self.__is_5g_enable is True:
            print("5g is enabled")
        else:
            print("5g is not enabled,is using 4g")

    def call_by_5g(self):
        self.__check_5g()
        print(" is calling")
phone1=Phone()
phone1.call_by_5g()